Pick That Up!
I was in a subway, the type that runs underground. Two teenagers were sitting there eating cupcakes and some other junk they brought onto the train. One of them just throws his garbage on the floor. So I just said, “HEY! Pick that up!” He sheepishly picked it up and gave me that look kids give to teachers when they get caught doing something they know they’re not supposed to do.
Story credit: Reddit / Mun-Mun